Track-type machines are in widespread use in construction, mining, forestry, and other similar industries. The undercarriage of such track-type machines utilizes track assemblies, rather than wheels, to provide ground-engaging propulsion. Such track assemblies may be preferred in environments, such as the environments identified above, where creating sufficient traction is problematic. Specifically, rather than rolling across a work surface on wheels, track-type machines utilize one or more track assemblies that include an endless loop of coupled track links defining outer surfaces, which support ground-engaging track shoes, and inner surfaces that travel about one or more rotatable track-engaging elements, such as, for example, drive sprockets, idlers, tensioners, and rollers.
During typical operation of the track-type machine, the various moving parts of the track assembly may undergo significant wear. Specifically, for example, the drive sprockets, idlers, rollers, and track links may all experience wear from nearly constant metal-to-metal contact. Of particular interest is the wear between the drive sprockets and bushings. According to an exemplary embodiment, pin and bushing assemblies may couple first and second sets of track links of the track assembly. Specifically, bushings, which may or may not be configured to rotate, may be positioned about track pins and may engage the drive sprocket when the sprocket is driven in a forward, or a reverse, rotational direction. Such interaction may cause significant wear on contact surfaces of the bushings and drive sprocket and, as a result, may change the operating pitch between the components, resulting in increased load stresses and possibly failure of the track assembly.
As a result, numerous strategies have been developed to attempt to prolong the useful life of some of the track assembly components. For example, U.S. Pat. No. 3,960,412 discloses a pin bushing having an outer substantially oval configuration to define a pair of oppositely disposed wear surfaces. Sprocket teeth, at their roots, engage a first wear surface of the pair of oppositely disposed wear surfaces during operation of the track assembly. Once the first wear surface is worn to a predetermined point, segments defining the sprocket may be replaced with segments having a higher pitch, thus moving the pitch diameter back to approximately the original pitch diameter, as defined by the pin bushing and sprocket combination. After additional wear occurs, the pin bushing may be rotated such that roots of the sprocket teeth engage a second wear surface of the pair of wear surfaces. In this configuration, the segments having a higher pitch may be replaced with the original sprocket segments. While this method of replacing sprocket segments may serve to prolong the useful life of relevant portions of the track assembly, it should be appreciated that there is a continuing need for improving various operational characteristics of track assemblies.
The present disclosure is directed to one or more of the problems set forth above.